Infinite loop in Keycloak SAML parser crashes the service
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-835.
Summary
Red Hat build of Keycloak 26.4 and 26.6 are affected by an infinite loop in the SAML 1.1 assertion parser, classified as CWE-835. The loop occurs when the parser handles an AuthorityBinding element within an authentication statement, following an incomplete fix for an earlier flaw. An unauthenticated remote attacker can make the parser consume all available memory, crashing the entire Keycloak service and making it unavailable to users.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
A flaw was found in the SAML 1.1 assertion parser of Keycloak, a tool used for identity and access management. The issue occurs when the parser handles a specific element called AuthorityBinding within an authentication statement. Due to an incomplete fix for a previous vulnerability, the parser can enter an infinite loop that consumes all available memory, causing the entire Keycloak service to crash and become unavailable to users.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.4 | — | 26.4.17-2 | Patch available | CNA |
| Red Hat | Red Hat build of Keycloak 26.4 | — | 26.4-29 | Patch available | CNA |
| Red Hat | Red Hat build of Keycloak 26.4 | — | 26.4-30 | Patch available | CNA |
| Red Hat | Red Hat build of Keycloak 26.4.17 | — | — | Not affected | CNA |
| Red Hat | Red Hat build of Keycloak 26.6 | — | 26.6.8-2 | Patch available | CNA |
| Red Hat | Red Hat build of Keycloak 26.6 | — | 26.6-24 | Patch available | CNA |
| Red Hat | Red Hat build of Keycloak 26.6 | — | 26.6-24 | Patch available | CNA |
| Red Hat | Red Hat build of Keycloak 26.6.8 | — | — | Not affected | CNA |
| Red Hat | Red Hat build of Keycloak 26.6.8 | — | — | Not affected | CNA |
| Red Hat | Red Hat Single Sign-On 7 | — | — | Not affected | CNA |
- Red Hat build of Keycloak 26.4 VendorRed Hat Affected — Fixed in 26.4.17-2 Patch available CNA
- Red Hat build of Keycloak 26.4 VendorRed Hat Affected — Fixed in 26.4-29 Patch available CNA
- Red Hat build of Keycloak 26.4 VendorRed Hat Affected — Fixed in 26.4-30 Patch available CNA
- Red Hat build of Keycloak 26.4.17 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat build of Keycloak 26.6 VendorRed Hat Affected — Fixed in 26.6.8-2 Patch available CNA
- Red Hat build of Keycloak 26.6 VendorRed Hat Affected — Fixed in 26.6-24 Patch available CNA
- Red Hat build of Keycloak 26.6 VendorRed Hat Affected — Fixed in 26.6-24 Patch available CNA
- Red Hat build of Keycloak 26.6.8 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat build of Keycloak 26.6.8 VendorRed Hat Affected — Fixed in — Not affected CNA
- Red Hat Single Sign-On 7 VendorRed Hat Affected — Fixed in — Not affected CNA
Remediation
Upgrade Red Hat build of Keycloak 26.4 to 26.4.17-2, 26.4-29 or 26.4-30, and Red Hat build of Keycloak 26.6 to 26.6.8-2 or 26.6-24. Red Hat advisories RHSA-2026:95759, RHSA-2026:95760, RHSA-2026:95761 and RHSA-2026:95762 provide these fixes.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Red Hat 4 advisories
- RHSA-2026:95762 Released 2026-11-06 · Red Hat rating ImportantRed Hat build of Keycloak 26.6.8 Images Security Update
- Red Hat build of Keycloak 26.6 rhbk/keycloak-operator-bundle, rhbk/keycloak-rhel9, rhbk/keycloak-rhel9-operator
- RHSA-2026:95760 Released 2026-11-06 · Red Hat rating ImportantRed Hat build of Keycloak 26.4.17 Images Security Update
- Red Hat build of Keycloak 26.4 rhbk/keycloak-operator-bundle, rhbk/keycloak-rhel9, rhbk/keycloak-rhel9-operator
- RHSA-2026:95761 Released 2026-11-06 · Red Hat rating ImportantRed Hat build of Keycloak 26.6.8 Security Update
- Red Hat build of Keycloak 26.6.8
Show 1 more Red Hat advisories
- RHSA-2026:95759 Released 2026-11-06 · Red Hat rating ImportantRed Hat build of Keycloak 26.4.17 Security Update
- Red Hat build of Keycloak 26.4.17
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat build of Keycloak 26.4 | Fixed | RHSA-2026:95760 |
| Red Hat build of Keycloak 26.4.17 | Fixed | RHSA-2026:95759 |
| Red Hat build of Keycloak 26.6 | Fixed | RHSA-2026:95762 |
| Red Hat build of Keycloak 26.6.8 | Fixed | RHSA-2026:95761 |
Not affected: 1 product
- Red Hat Single Sign-On 7
Timeline
- 2026-11-05 Threatist record created from CVE-2026-110931
- 2026-11-05 Alias added: GHSA-w9c8-6pxq-5xf8
- 2026-11-05 Affected versions changed · Red Hat
- 2026-11-05 CVSS score added · Red Hat
- 2026-11-06 Fix available: [email protected], [email protected], [email protected] · CNA
- 2026-11-06 2 new references · CNA
- 2026-11-06 Fix available: RHSA-2026:95761 · Red Hat
- 2026-11-06 Fix available: Red Hat build of Keycloak 26.6.8 · Red Hat
- 2026-11-06 Fix available: rhbk/[email protected], rhbk/[email protected], rhbk/[email protected] +3 · CNA
- 2026-11-06 2 new references · CNA
- 2026-11-06 Fix available: RHSA-2026:95760 · Red Hat
- 2026-11-06 Fix available: RHSA-2026:95762 · Red Hat
- 2026-11-06 Fix available: RHSA-2026:95759 · Red Hat
- 2026-11-06 Fix available: Red Hat build of Keycloak 26.4, Red Hat build of Keycloak 26.4.17, Red Hat build of Keycloak 26.6 · Red Hat
- 2026-11-07 EPSS moved to the 50th–90th percentile
- 2026-11-07 Priority changed: MEDIUM → LOW
References
More Red Hat vulnerabilities
- TI-2019-15875 Protection mechanism failure in Jenkins Pipeline: Groovy Plugin KEVCVSS 3.1CRITICAL 9.9
- TI-2019-15874 Protection mechanism failure in Jenkins Script Security Plugin KEVCVSS 3.1CRITICAL 9.9
- TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
- TI-2019-05363 Code injection in Elastic Kibana KEVCVSS 3.1CRITICAL 10.0
- TI-2019-03949 Out-of-bounds write in ESXi and Horizon DaaS KEVCVSS 3.1CRITICAL 9.8
- TI-2018-16080 A code execution vulnerability exists in the Stapler web framework used by Jenkins 2.153… KEVCVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-110931 · CVE Program
- CVE-2026-110931 · NVD
- FIRST EPSS
- GHSA-w9c8-6pxq-5xf8 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-110931 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences